docs: def when_values(self, **criteria):
          """
          By default, ``Behold`` objects call ``str()`` on all variables before
          sending them to the output stream.  This method enables you to filter on
          those extracted string representations.  The syntax is exactly like that
          of the ``when_context()`` method.  Here is an example.
  
          .. code-block:: python
  
             from behold import Behold, Item
  
             items = [
                Item(a=1, b=2),
                Item(c=3, d=4),
             ]
  
             for item in items:
                # You can filter on the string representation
                Behold(tag='first').when_values(a='1').show(item)
  
                # Behold is smart enough to transform your criteria to strings
                # so this also works
                Behold(tag='second').when_values(a=1).show(item)
  
                # Because the string representation is not present in the local
                # scope, you must use Django-query-like syntax for logical
                # operations.
                Behold(tag='third').when_values(a__gte=1).show(item)
          """
          criteria = {k: str(v) for k, v in criteria.items()}
          self._add_value_filters(**criteria)
          return self